Isolation of cellulose from rice straw and its conversion into cellulose acetate catalyzed by phosphotungstic acid

• Published in: Carbohydrate polymers Vol. 94; no. 1; pp. 71 - 76
• Main Authors: Fan, Guozhi, Wang, Min, Liao, Chongjing, Fang, Tao, Li, Jianfen, Zhou, Ronghui
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.04.2013; Elsevier
• Subjects: acetic acid; acetic anhydride; Acetic Anhydrides - chemistry; Acetylation; Agronomy. Soil science and plant productions; Applied sciences; Biological and medical sciences; Catalysis; catalysts; cellulose; Cellulose - analogs & derivatives; Cellulose - chemical synthesis; Cellulose - chemistry; Cellulose - isolation & purification; Cellulose acetate; Cellulose and derivatives; Exact sciences and technology; Fourier transform infrared spectroscopy; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; hemicellulose; Hydroxides - chemistry; Kinetics; lignin; Natural polymers; Oryza - chemistry; Particle Size; Phosphotungstic acid; Phosphotungstic Acid - chemistry; Physicochemistry of polymers; Plant Components, Aerial - chemistry; Potassium Compounds - chemistry; potassium hydroxide; Powder Diffraction; Rice straw; Solubility; Solvents - chemistry; Spectroscopy, Fourier Transform Infrared; Use of agricultural and forest wastes. Biomass use, bioconversion; X-Ray Diffraction; Phosphotungstic acid; Acetylation; Cellulose acetate; Rice straw; Catalytic reaction; Tungsten compound; Cellulose; Delignification; Chemical isolation; Lignocellulosics; Acid catalysis; Crystallinity; Experimental study; Rice by product; Acetic anhydride; Esterification; Vegetal waste; Heteropolyacid; Chemical modification; Physical separation; Phosphorus compound; Cellulose organic ester; Catalyst activity
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2013.01.073

► Cellulose was isolated from rice straw via treatment with KOH and CH3COOH. ► Cellulose derived from rice straw was employed to synthesize cellulose acetate. ► Phosphotungstic acid was found to be an effective catalyst for the acetylation of cellulose. ► Degree substitution of cellulose acetate is dependent on the amount of catalyst. Cellulose was isolated from rice straw by pretreatment with dilute alkaline and acid solutions successively, and it was further transferred into cellulose acetate in the presence of acetic anhydride and phosphotungstic acid (H3PW12O40·6H2O). The removal of hemicellulose and lignin was affected by the concentration of KOH and the immersion time in acetic acid solution, and 83wt.% content of cellulose in the treated rice straw was obtained after pretreatment with 4% KOH and immersion in acetic acid for 5h. Phosphotungstic acid was found to be an effective catalyst for the acetylation of the cellulose derived from rice straw. The degree of substitution (DS) values revealed a significant effect for the solubility of cellulose acetate, and the acetone-soluble cellulose acetate with DS values around 2.2 can be obtained by changing the amount of phosphotungstic acid and the time of acetylation. Both the structure of cellulose separated from rice straw and cellulose acetate were confirmed by FTIR and XRD.